Friendship and Delinquency: Selection and Influence Processes in Early Adolescence

Positive association of relevant characteristics is a widespread pattern among adolescent friends. A positive association may be caused by the selection of similar others as friends and by the deselection of dissimilar ones, but also by influence processes where friends adjust their behavior to each other. Social control theory argues that adolescents select each other as friends based on delinquency. Differential association theory, on the other hand, argues that adolescent friends influence each other's delinquency levels. We employ new statistical methods for assessing the empirical evidence for either process while controlling for the other process. These methods are based on ‘actor‐oriented’ stochastic simulation models. We analyze longitudinal data on friendship networks and delinquent behavior collected in four waves of 544 students in 21 first‐grade classrooms of Dutch secondary schools. Results indicate that adolescents select others as friends who have a similar level of delinquency compared with their own level. Estimates of the social influence parameters are not significant. The results are consistent with social control theory but provide no support for differential association theory.     

A Risk Assessment Model for Enterotoxigenic Staphylococcus aureus in Pasteurized Milk: A Potential Route to Source‐Level Inference

This article describes a probabilistic model that quantifies hazards that arise from Staphylococcus aureus in milk that is sold as pasteurized in the United Kingdom. The model is centered on coupled dynamics for S. aureus populations, staphylococcal enterotoxins, and the concentration of alkaline phosphatase throughout the milk chain. The chain includes farm collection and storage of pooled milk, further pooling for off‐farm processing, high temperature short time thermal processing, and possible postprocess contamination. The model is implemented as a Bayesian belief network. The results indicate that milk sold as pasteurized is relatively safe with respect to the hazards associated with S. aureus and that most risk is associated with small scale on‐farm processing. An additional analysis of likelihood ratios shows that alkaline phosphatase concentrations in filler tank milk are a good indicator of potential hazards and that these concentrations, in conjunction with other measurements, can be used effectively to discriminate over possible failure modes. The ability to discriminate over potential failure modes can support preemptive actions, such as maintenance or hygiene, which assist with milk chain management and, over extended periods, accumulate to drive improved safety, efficiency, and security.     

White Ethnic Diversity and Community Attachment in Small Iowa Towns

Objectives . This study examines the relationship between white ethnic diversity and community attachment in 99 small Iowa towns. Methods . Our data come from the U.S. Census Bureau and the Rural Development Initiative (RDI) at Iowa State University. The RDI data, which consist of interviews with approximately 110 people in each of the 99 towns, are used to develop a community attachment score for each town. These scores serve as the dependent variable in ordinary least squares regression models to assess the extent to which ethnic diversity is related to attachment. Results . The findings show that towns with high levels of white ethnic diversity tend to have low levels of community attachment. Moreover, residents of diverse towns tend to view their communities with more suspicion and tend to be less involved in community activities than citizens in more homogeneous towns. Conclusions . Looked at narrowly, these results indicate that white ethnic diversity may be detrimental to community building in small Iowa towns. More broadly, the findings provide support for the idea that white ethnic diversity is alive and well in America.     

Software variety and hardware value: a case study of complementary network externalities in the microcomputer software industry

We estimate the effects of software provision on the valuation of hardware in the early microcomputer industry, covering the period 1981–1986. Since hardware and software technologies `co-evolve,' a discussion of the economic and technological relationships is provided to clarify the nature of the relationship between software variety and hardware price.     

Work-related reproductive health: a review

This paper reviews the literature concerning the impact of work on reproductive health. In doing so, it offers a framework model for guiding future research and practice. Contemporary models of occupational health usually identify at least two pathways linking exposure to workplace hazards to their effects on health. The study of work-related reproductive health has been largely restricted to the effects of the more tangible and physical hazards of work mediated by a largely physico-chemical pathway. However, the growth of research into the psycho-physiological influence of stress on reproductive health provides a new direction for research in this domain with the exploration of a complementary pathway. The extension of this new approach into the investigation of the effects of work design and management on reproductive health represents a potentially important and further development.     

Social trends and corporate plans

All business in working out their future relationships, need to have a continuous reading of social change.This article outlines the approach and conclusions of a firm which is involved with providing an ongoing study service for this aspect of planning.     

Spontaneous evolution of social exchange—An experimental study

Each of several exchange partners owns a specific commodity which she can share with others. Unlike in other social dilemma scenarios like prisoners’ dilemma, public goods games, etc., voluntary cooperation relies on bilateral exchanges whose profitabilities are interdependent. How will mutual sharing evolve? Will it include all group members or will smaller groups be more efficient? Our experimental data shed partly new light on older topics: cooperation is now relation specific, allowing for discrimination; group size effects are explored dynamically rather than in one-shot interaction; and, finally, we have weakened demand effects for voluntary cooperation by realistic efficiency gains.